Speech comprehension plays a critical role in the well-being of most children and adults. However, speech signals are rapidly-changing, complex patterns of sound that challenge even the efficient auditory perceptual systems of adults with normal hearing and a lifetime of linguistic experience. By examining how adults with normal hearing overcome the challenges presented by speech, it will be possible to develop auditory environments and training paradigms to improve speech processing in individuals with additional challenges including young children, second language learners, and people with partial hearing loss. Selective attention is an important tool in many perceptually challenging situations, as it allows people to preferentially process the information that is most relevant to their goals. The current proposal is designed to determine the mechanistic role of selective attention in skilled speech processing. Recent evidence indicates that adults listening to their native language selectively attend to natural speech at times that include word-initial segments. Directing temporally selective attention to the onsets of words may be an effective strategy since word-initial segments are highly informative, and can be used to predict upcoming information (i.e., the remaining portion of the word) that may not need to be processed in as much detail. However, the underlying mechanism of this cognitive process remains unexplored. The specific goals of this proposal are to assess how listeners direct attention to word onsets based on the following potential cues: 1) the recognition of a word that precedes a new onset, 2) the predictability of upcoming information, and 3) the interaction and competition of these cues. These questions will be examined by measuring event-related potentials (ERPs) elicited by word onsets in a tightly controlled artificial language. Recognition training and predictability of critical words will be manipulated in separate experiments and together. Evidence concerning how temporally selective attention functions during speech perception will provide insight into why speech perception is difficult for some populations, including second language learners, normally developing and language impaired children, older adults, and individuals with monaural or partial hearing loss. Understanding how skilled listeners know when to pay attention during spoken language will inform procedures aimed to enhance speech perception in populations and situations for which speech comprehension is especially difficult.